Background While the association between maternal age and the risk of chromosomal anomalies is well established, uncertainty remains for structural (ie, non-genetic) anomalies. This study used data from North East England and North Cumbria to investigate the relationship between maternal age, young or advanced and the risk of structural congenital anomalies.

Method Congenital anomaly cases without known chromosomal or genetic features, delivered between 1985 and 2004, were identified from the population-based Northern Congenital Abnormality Survey. The age distribution of case mothers and the general maternal population were compared using χ² tests. The relative odds of a structural anomaly for young maternal age (below 20 years) and advanced maternal age (30 years or over), were determined for all groups and subtypes with at least 100 cases.

Results 11 422 pregnancies were affected by a structural congenital anomaly. The odds of a pregnancy affected by a structural anomaly were significantly greater among young mothers (OR 1.13 (95% CI 1.07 to 1.20), p<0.001), but not those of advanced age (1.01 (0.97 to 1.06), p=0.51). By group, young maternal age was associated with significantly increased odds of nervous system anomalies (p=0.02), abdominal wall anomalies (p<0.001), musculoskeletal anomalies (p=0.007) and multiple anomalies (p=0.006). Advanced maternal age was associated with significantly increased odds of musculoskeletal anomalies (p=0.04), and significantly reduced odds of nervous system (p<0.001) and abdominal wall anomalies (p<0.001).

Conclusion This study found evidence of an association between maternal age, young and advanced and the risk of certain structural congenital anomalies.